Immobilization of green tea extract on polypropylene films to control the antioxidant activity in food packaging

- Polypropylene-anhydride maleic grafted polypropylene-green tea for food active package
- Maleic anhydride grafted into polypropylene changed polymer release ability.
- No changes or slight improvements induced by new formulations on blend effectiveness
- Maleic anhydride polypropylene: prolonging antioxidant activity after sterilization
- Maleic anhydride polypropylene decreases antioxidant release due to microwave heating.

In this work, we report the successful immobilization of green tea extract, as a natural antioxidant, on polypropylene through the incorporation of anhydride maleic grafted polypropylene on polymer formulation owing to control active compound release and prolong antioxidant activity. The extruded films were thermally characterized showing that the incorporation of green tea extract improved polymer stability, and the presence of grafted polymer did not affect polymer morphology. Green tea components release profiles depending on the type of food and polymer formulation. The use of grafted polypropylene changed the ability of the polymer to release green tea antioxidants; the amount of components released decreased with an increasing degree of grafted polypropylene. Materials were submitted to sterilization and microwave heating conditions. The immobilization of the active compounds implied a lower release during these typical food package treatments, and the available antioxidant components on the modified materials presented a good correlation with the antiradical activity toward ABTS+ radicals, prolonging their antioxidant ability.